"Today is the first page in a new chapter of our mission to improve access to the cultural and educational treasures we know as books," Abraham Murray, the Product Manager of Google Books wrote on the company blog.

The e-reader, which can be downloaded across different platforms including Apple products, as well as accessed through computers, makes it easy for consumers to purchase e-books similar to how iTunes works for music.

In addition to threatening other e-bookstores — mainly Borders and Barnes & Noble — the tech giant's new product presents a huge threat to e-book readers like the Kindle and Amazon Nook which require consumers to purchase an entire new product in order to read books on the go. With the Google bookstore, users can download full books to their iPhones or iPads or other smartphones.

"This is basically a small stake in the ground," Allen Weiner, of technology research firm Gartner told Marketwatch. "You have to think about what this will look like in a year. It's a warning shot as to what's to come from Google in terms of the approach they are going to take towards a plethora of devices."

On an Apple iPhone, more than 3 million e-books can be downloaded easily through a free application for a little under the list price. Users can even look at a sample of the book before downloading it.

The product uses cloud technology, which means book fans can download the books on their computers and then read them on the go. And while the debut at 3 million is impressive, the company expects it to continue to grow.

"Launching Google eBooks is an initial step toward giving you greater access to the vast variety of information and entertainment found in books," Murray said. "Our journey has just begun."